Lord Justice Leveson has recommended the introduction of the first press law in Britain since the 17th century – proposing that a statutory body such as Ofcom should take responsibility for monitoring an overhauled Press Complaints Commission.

The proposal – made despite the fierce opposition of Fleet Street to the introduction of statute – is designed to reassure the public that newspapers are subject to an effective and independent regulator to prevent a repetition of phone hacking or other scandals.

In the 56-page summary to his wide-ranging 2,000-page report, Leveson says the purpose of legislation is "not to establish a body to regulate the press". But he warns that if newspapers are not prepared to join a revamped PCC it will be necessary to force Ofcom to act as a "backstop regulator".

Leveson says it is necessary for a body like Ofcom to monitor a revamped PCC to "reassure the public of its independence" – but insists that legislation would "not establish a body to regulate the press, that is for the press to do".

His report also contains criticisms of politicians for becoming too close to press owners – but does not single out any individuals, other than making some criticism of former culture secretary Jeremy Hunt – and complains that the Metropolitan police should have done more to investigate phone hacking once it emerged that the practice appeared to be more widespread than the actions of a single rogue reporter in 2009 and 2010.

The judge insists that he "cannot recommend" the model of PCC reform draw up by Lords Black and Hunt, because it would be insufficiently independent of the press. "It is still the industry marking its own homework," the judge said in a press conference publishing the report – because of the level of industry influence in making key appointments. The appointment of the chair of a revamped PCC would have to be done by a "fair and open process" with a majority on the appointments commission that were "independent of the press".

Leveson also said that his proposed new law would enshrine "for the first time" a "legal duty on the government to protect the freedom of the press" – an attempt to provide a US-style "first amendment" provision in the UK for the first time.

His model legislation would also allow the new body to set up a low-cost libel and privacy tribunal to handle complaints instead of the courts – and provide "benefits in law" to those who signed up. Those who did not sign up would be denied the ability to reclaim the often substantial costs of litigation – even if they won – from complainants bringing libel, privacy or other media-related actions.

The proposed press law is one of a string of conclusions in a summary that contains withering criticism of standards in the industry – but the shorter document rarely singles out individual newspapers.

"There have been too many times when, chasing the story, parts of the press have acted as if its own code, which it wrote, simply did not exist. This has caused real hardship and, on occasion, wreaked havoc with the lives of innocent people whose rights and liberties have been disdained," the judge writes.

Leveson says people like the McCanns and the parents of Milly Dowler had "devastating" experiences at the hands of the press, and that parts of the industry viewed celebrities as little more than "fair game".

There is specific criticism levelled at the News of the World, and by implication, its owner, Rupert Murdoch's News Corporation. Leveson says that "most responsible corporate entities would be appalled that employees were or could be involved in the commission of crime in order to further their business. Not so at the News of the World."

In the summary there is little criticism of individual politicians or media owners. But the political handling of News Corp's BSkyB bid is singled out, and, while Leveson says there is no evidence that Jeremy Hunt, the then culture secretary, displayed "actual bias", the exchanges between his former special adviser Adam Smith and James Murdoch's adviser Fred Michel did give rise to "a perception of bias".

The judge treads very carefully when it comes to discussing relations between owners, editors and politicians. But he says that "over the last 30-35 years and probably much longer" politicians of the government and official opposition have "had or developed too close a relationship with the press in a way which has not been in the public interest".

He adds that frontbenchers in government and opposition should disclose their meetings with "executive decision-makers of the press" and disclose "by way of general estimate" basic information about "the frequency and density of other communications" – such as correspondence, phone, text and email.

There is criticism of the Metropolitan police, and specifically former assistant commissioner John Yates, for failing to reopen the investigation into phone hacking after articles in the Guardian and the New York Times concluded that the practice went wider than a single "rogue reporter" in 2009 and 2010.

He says that he regretted that Yates "did not reflect on whether he should be involved in an investigation into the newspaper at which he had friends, including one who was the deputy editor": Neil Wallis.

He says that Yates was wrong to conclude, after the Guardian published its investigation in July 2009, on the same day that "there was no turning back. A defensive mindset was then established which affected all that followed."

But he says Yates and other officers involved in those decisions made mistakes — and "the integrity of the officers who gave evidence … shone through". He also says that the police were correct to limit the initial 2006 investigation into hacking into the material seized from private investigator Glenn Mulcaire. That decision was "fully justified" because of wider counter-terrorism priorities.